The latest environmental report on the Keystone XL pipeline should make it easier for President Barack Obama to climb down off the fence and finally approve the controversial, privately financed $5.3-billion construction project.

He's waited long enough trying to navigate a long-running dispute between key Democratic constituencies -- environmentalists concerned about pollution and climate change and labor unions that want the 1,950 construction jobs the project will deliver. The pipeline could transport 830,000 barrels of crude oil a day from tar sands in Alberta, Canada, to refineries on the Gulf of Mexico. The report the U.S. State Department released Friday said that the pipeline would result in lower greenhouse gas emissions and less risk from spills than the alternatives of transporting the oil by truck, train or ship. This is an international issue requiring presidential approval because the pipeline crosses our border.

The southern stretch of the pipeline, from Oklahoma to the Gulf Coast, is already in operation. Obama rejected the northern section in 2012 because it posed an undue risk to groundwater in Nebraska. The route has since been modified to protect the vast Ogallala aquifer that stretches across parts of eight western states. Obama knows that even if he again rejects the northern leg, the oil will still be extracted, a process that generates more greenhouse gases than the extraction of conventional oil.

The other environmental concern is spills, a greater risk with alternatives such as moving the oil to the Gulf by rail. Several recent derailments of trains carrying oil, including in Mississippi on Friday and in North Dakota in December, led the National Transportation Safety Board to recommend that oil-laden trains avoid populated areas. Tanker cars carrying crude or ethanol from the West and Midwest to refineries in Linden, N.J., routinely pass through upstate New York.

Obama should approve the pipeline so the oil from Alberta can be transported to refineries in the United States in the safest way possible.